18. 两个几何的差集

public Geometry symDifference(Geometry other) {
    if (this.isEmpty() || other.isEmpty()) {
        if (this.isEmpty() && other.isEmpty()) {
            return OverlayOp.createEmptyResult(4, this, other, this.factory);
        }
        if (this.isEmpty()) {
            return other.copy();
        }
        if (other.isEmpty()) {
            return this.copy();
        }
    }
    checkNotGeometryCollection(this);
    checkNotGeometryCollection(other);
    return SnapIfNeededOverlayOp.overlayOp(this, other, 4);
}

19.返回几何体的缓冲区（一）

    默认样式

public Geometry buffer(double distance) {
    return BufferOp.bufferOp(this, distance);
}

20.返回几何体的缓冲区（二）

参数分别是：缓冲区宽度、端点圆弧样式

//

线段末端样式

public static final int CAP_ROUND = 1;
public static final int CAP_FLAT = 2;
public static final int CAP_SQUARE = 3;//

quadrantSegments 圆弧处，线段数量

public static final int JOIN_ROUND = 1;  (默认)一个半圆
public static final int JOIN_MITRE = 2;  一条垂直于末端的直线
public static final int JOIN_BEVEL = 3;
public static final int DEFAULT_QUADRANT_SEGMENTS = 8;

//源方法
public Geometry buffer(double distance, int quadrantSegments) {
    return BufferOp.bufferOp(this, distance, quadrantSegments);
}//调用示例

Geometry buffer = laneToQuery.buffer(bufferDis, BufferParameters.DEFAULT_QUADRANT_SEGMENTS);

  圆弧线段数

 quadrantSegments参数示例：JOIN_ROUND = 1

quadrantSegments参数示例：JOIN_ROUND = 2

 quadrantSegments参数示例：JOIN_ROUND = 3

 quadrantSegments参数示例：DEFAULT_QUADRANT_SEGMENTS = 8

21.返回几何体的缓冲区（三）

//源方法
public Geometry buffer(double distance, int quadrantSegments, int endCapStyle) {
    return BufferOp.bufferOp(this, distance, quadrantSegments, endCapStyle);
}

//调用示例
Geometry buffer = laneToQuery.buffer(bufferDis, BufferParameters.DEFAULT_QUADRANT_SEGMENTS, BufferParameters.CAP_FLAT);

设置线段末尾端点样式

endCapStyle参数示例：CAP_ROUND = 1   (默认)一个半圆

endCapStyle参数示例：CAP_FLAT = 2   一条垂直于末端的直线

endCapStyle参数示例：CAP_SQUARE = 3

22.返回当前的几何的覆盖面几何

public Geometry convexHull() {
    return (new ConvexHull(this)).getConvexHull();
}

参考：SFS-简单要素标准

网址：1.2. II. SFS-简单要素标准 — OGC标准规范 文档 (osgeo.cn)